1. Field of the Invention
The present invention relates to a mandrel for a medical endoscope.
2. Description of Related Art
As is known, medical endoscopes for examination or operation purposes, for example urological endoscopes, consist of a tubular outer jacket, into which an inner, rod-shaped, solid mandrel is introduced. The mandrel has a profiled mandrel head. Upon insertion of the endoscope, for example into a ureter of a patient, the profiled mandrel head projects out of the tubular jacket of the endoscope. The mandrel head is locked in this position of protrusion with respect to the tubular jacket of the endoscope using releasable securing means. The securing means are arranged on the end side of the endoscope jacket at its outer end lying opposite the insertion side. The profiled mandrel head, which projects from the tubular jacket, has the task of gradually widening the ureter during the process of insertion of the endoscope. In known endoscopes, the external diameter of the mandrel is kept slightly smaller than the internal diameter of the endoscope jacket. This results in the external diameter of the mandrel also being smaller than the external diameter of the endoscope jacket. This disadvantage is also to be found in endoscopes for performing surgical operations. These devices too have, at that end of the jacket of the endoscope to be inserted into the ureter for example, a profiled endpiece whose design is dependent on the operation to be performed. At that end of the endoscope jacket to be inserted, all known endoscopes form around the mandrel head a protruding edge, whose protrusion with respect to the mandrel head corresponds to the wall thickness of the endoscope jacket. Upon insertion of the endoscope, the border or the outer edge of the endoscope jacket leads inevitably to injuries to the ureter. When the endoscope is used for urological examinations, it is true that the injuries to the wall of the ureter scar over, but the scar formation is known to lead to narrowing of the ureter canal, and this often results in continuous pain and necessitates renewed surgical intervention.
The above designs for known urological endoscopes are also for endoscopes with mandrels which are to be inserted into further canals in the patient, and in which endoscopes, following insertion of the endoscope with the mandrel, the mandrel is subsequently withdrawn in order to insert into the jacket of the endoscope optical devices or electrically operated surgical appliances, for example electrically driven scalpels.